Info Favorites Register Log in
myArmoury.com Discussion Forums

Forum index Memberlist Usergroups Spotlight Topics Search
Forum Index > Historical Arms Talk > Blunt Force Trauma - Medieval Arrows Reply to topic
This is a standard topic Go to page Previous  1, 2, 3, 4 
Author Message
Marc Ritz




Location: Manila, Philippines
Joined: 02 Aug 2013

Posts: 6

PostPosted: Mon 16 May, 2016 9:50 am    Post subject:         Reply with quote

The topic discussion often makes use of comparisons with firearms and usually fails to consider a few physics principles.

An arrow strike is a more elastic collision than any firearm collision.

Elastic collision are those in which the total kinetic energy remains the same. Meaning, no energy was converted into other forms of energy like heat or deformations. A lead bullet will waste more energy than an arrow.

Second, we have to consider the implications of projectile masses. The ratio between the masses of the bodies (armoured target and projectile) will determine how much energy is retained in the projectile. The more massive the projectile, the more energy it will impart on the target.

It's been mentioned before by Benjamin, and it's been accepted by the hunting community at large that the more meaningful quantity when discussing arrow penetration is momentum. It just so happens that momentum is also the most meaningful quantity when comparing how effectively an object can impart it's energy on to another object.

It should be quite intuitive actually. Imagine you would play mini-golf with a bowling ball. If you used a high mass sledge hammer, you could get to move the bowling ball quite easily. Because the sledge hammer has a lot of momentum and it's greater mass imparts kinetic energy on the ball more effortlessly. A golf club however with it's decreased mass may very well be able to generate more kinetic energy but won't move the ball easily. Because the kinetic energy will remain in the golf club as it rebounds from the bowling ball and gives you bad handshock.

You can only use standardized values for kinetic energy and its damage potential when using comparable projectiles. It makes no sense to compare the kinetic energy damage potential of a firearm bullet with that of an arrow or even sword. To do that points towards a lack of good research data (because why else would anyone resort to such data) and of a compromised understanding of physics.

Can we come up with a conversion factor to make comparisons between firearm bullets and arrows easier? Maybe! But that would require research to back up any proposed model.
View user's profile Send private message
Karl G




Location: Australia
Joined: 25 Apr 2016

Posts: 66

PostPosted: Mon 16 May, 2016 7:55 pm    Post subject:         Reply with quote

Jeffrey Faulk wrote:
Karl G wrote:
On the long running discussions of arrow effectiveness my opinion remains the same, the medieval enthusiast should avail himself of some hunting experience. Specifically high powered rifles 2000fps+, low powered(under 2000fps= handguns, shotguns and muzzleloaders) and modern vertical bows and crossbows. This will put the great range of paradigms, anecdotes, statements and buzzwords he may have heard( such as 'blunt trauma) into a categorical perspective and clear up a lot of discussions before they even start. As to the question will arrows not causing penetrating wounds in armour, still cause blunt trauma. The answer is possibly yes, in the sense of a contusion may be formed. Will the blunt trauma/contusion be lethal or even disabling? Rare/doubtful.


Blunt arrows have been used for millennia in hunting, largely for small game (think squirrels and rabbits) and birds. The blow is quite sufficient to kill them without tearing up the relatively small amount of meat on those animals.

I'm not sure how well modern hunting translates into discussion of medieval armor and weapons. There is a degree of relevance, but a compound bow is a long shot from a yew longbow. And it's not like animals tend to go about wearing armour, armadillos and turtles notwithstanding...


This is my point getting buzzwords mixed up.

1.Blunts do not kill by blunt trauma, but by penetrating trauma and blood loss. The idea of the blunt is to reduce skin damage in the case of recovering skins and also is less damaging to the tip itself. However it still penetrates and cuts blood bearing tissues and vessels to kill. If it can't penetrate the surface this will not occur. Where a blunt could 'pulverise' an animal into submission it is a fraction of human body weight.

2. The advantage of modern bows, compound, recurve and even crossbows of different types is the effects of arrows do not vary greatly. Trajectory and penetration differ to a degree but otherwise terminal effect is the same. Many choose to hunt at downgraded velocities or with actual longbows too so its all covered anyway.

As to firearms the main advantage of using both them and arrows removes any comparisons of their kinetic effects from creeping into these conversations. They are so far removed from arrow ballistics its not funny.

As Dan said in about the second post and the fellow above has said, they don't have a place in these conversations.A few shots at game and static materials it all becomes very clear even without physics knowledge.


Last edited by Karl G on Mon 16 May, 2016 8:12 pm; edited 1 time in total
View user's profile Send private message Send e-mail
Philip Dyer





Joined: 25 Jul 2013

Posts: 507

PostPosted: Mon 16 May, 2016 8:10 pm    Post subject:         Reply with quote

Karl G wrote:
Jeffrey Faulk wrote:
Karl G wrote:
On the long running discussions of arrow effectiveness my opinion remains the same, the medieval enthusiast should avail himself of some hunting experience. Specifically high powered rifles 2000fps+, low powered(under 2000fps= handguns, shotguns and muzzleloaders) and modern vertical bows and crossbows. This will put the great range of paradigms, anecdotes, statements and buzzwords he may have heard( such as 'blunt trauma) into a categorical perspective and clear up a lot of discussions before they even start. As to the question will arrows not causing penetrating wounds in armour, still cause blunt trauma. The answer is possibly yes, in the sense of a contusion may be formed. Will the blunt trauma/contusion be lethal or even disabling? Rare/doubtful.


Blunt arrows have been used for millennia in hunting, largely for small game (think squirrels and rabbits) and birds. The blow is quite sufficient to kill them without tearing up the relatively small amount of meat on those animals.

I'm not sure how well modern hunting translates into discussion of medieval armor and weapons. There is a degree of relevance, but a compound bow is a long shot from a yew longbow. And it's not like animals tend to go about wearing armour, armadillos and turtles notwithstanding...


This is my point that the average theorist gets his buzzwords mixed up.

1.Blunts do not kill by blunt trauma, but by penetrating trauma and blood loss. The idea of the blunt is to reduce skin damage in the case of recovering skins and also is less damaging to the tip itself. However it still penetrates and cuts blood bearing tissues and vessels to kill. If it can't penetrate the surface this will not occur.

2.Many modern bows, compound, recurve and even crossbows of different types will equate to velocities and hunting tips of longbows and other ancient bows. You can choose to hunt at downgraded velocities or an actual longbow too if you wish, and this also provides knowledge of point 1.

As to firearms the main advantage of using both them and arrows removes any comparisons of their kinetic effects from creeping into these conversations. They are so far removed from arrow ballistics its not funny, yet time and time again the medieval theorists compare 'well what do bullets do'...
So, would a sabot (basically minuture dart designed to be able to fire out of a gun) have physics more in common with arrows or bullets? Also, I've noticed that there have been alot of dicussions of 15th and 16th century breastplates and there ability to withstand musket and pistol shoot but no studies of 14th culverins, pipe guns, akes in comparision to earlier breastplates.
View user's profile Send private message
Timo Nieminen




Location: Brisbane, Australia
Joined: 08 May 2009
Likes: 1 page
Reading list: 1 book

Posts: 1,504

PostPosted: Mon 16 May, 2016 8:14 pm    Post subject:         Reply with quote

Marc Ritz wrote:
Elastic collision are those in which the total kinetic energy remains the same. Meaning, no energy was converted into other forms of energy like heat or deformations. A lead bullet will waste more energy than an arrow.


You don't want an elastic collision. You want to deform the target. Crush it, cut it, pierce it. That takes energy. That's where you want the energy to go. You don't want the energy to go into deforming the weapon (which happens to bullets), or into moving the target.

Typically, an arrow hit the target and stops, and the final speed of the target+arrow is small. The energy of that final motion is wasted; you want to minimise it. Still, that final motion is small, so it's a very inelastic collision. With a light and very fast bullet, it might go all the way through the target, and keep moving. That's wasted energy. Again, minimise. You want the collision to be as inelastic as possible.

Marc Ritz wrote:
Second, we have to consider the implications of projectile masses. The ratio between the masses of the bodies (armoured target and projectile) will determine how much energy is retained in the projectile. The more massive the projectile, the more energy it will impart on the target.


Generally, no. For an armoured target, it's the other way around. A heavier projectile with the same energy will be slower (and have more momentum), and the target is more easily moved by the projectile. More of the energy of the projectile goes into moving the target, rather than damaging the target.

The mass matters. While energy is conserved, kinetic energy is not. OTOH, momentum is always conserved. So, at the end of the collision, the target+projectile will have the same momentum as the initial projectile (assuming no pass-through). If you have a lot of momentum at the start, you'll have a lot of momentum at the end. Which means you'll have a lot of kinetic energy at the end, and less energy will have been used to damage the target.

So, if the projectile ends up stuck in the target, lower mass is better.

Marc Ritz wrote:
It's been mentioned before by Benjamin, and it's been accepted by the hunting community at large that the more meaningful quantity when discussing arrow penetration is momentum. It just so happens that momentum is also the most meaningful quantity when comparing how effectively an object can impart it's energy on to another object.


Momentum is the key when penetration is limited by viscous drag, such as in the case of penetration into soft tissue. This is the case in hunting, since most hunted animals are not armoured. For rigid metal armour, energy is the key quantity. This follows both from theory and lots of experiment. See, e.g., http://myArmoury.com/books/item.075068531X.html

This is because the energy lost to viscous drag is proportional to the speed or the speed squared; that energy isn't used to damage the target (disregarding shock waves and heating). Faster projectiles will waste more energy this way, so heavier (and therefore slower) projectiles will be better. Heavier, for the same kinetic energy, means more momentum.

Marc Ritz wrote:
It should be quite intuitive actually. Imagine you would play mini-golf with a bowling ball. If you used a high mass sledge hammer, you could get to move the bowling ball quite easily. Because the sledge hammer has a lot of momentum and it's greater mass imparts kinetic energy on the ball more effortlessly. A golf club however with it's decreased mass may very well be able to generate more kinetic energy but won't move the ball easily. Because the kinetic energy will remain in the golf club as it rebounds from the bowling ball and gives you bad handshock.


Elastic collision (as, ideally, the collision between ball and bat/club is) aren't the same thing as the inelastic collision between projectile and target. For the elastic collision, you'll get maximum energy transfer when the projectile and the target have the same mass (the billiard ball case) - the projectile stops, and the target moves (for a head-on collision). If the mass is greater than that, less energy is transferred to the target - the projectile keeps moving in the original direction. If the mass is lower, you'll have less energy transfer, and more momentum transfer - the projectile will bounce off, and end up moving in the opposite direction. Since it still has kinetic energy, less KE has been transferred. Since it has momentum in the opposite direction, more momentum has been transferred.

Marc Ritz wrote:
You can only use standardized values for kinetic energy and its damage potential when using comparable projectiles. It makes no sense to compare the kinetic energy damage potential of a firearm bullet with that of an arrow or even sword.


For going through armour, the geometry of the penetrator matters a lot. This is known. About 1000J of bullet has similar penetration to 100J of arrow (more, but those are nice round numbers). For doing damage to a target, it matters too. Crushing takes a lot more energy to do the same damage than cutting. But given that the topic is blunt trauma, the comparison is crushing vs crushing, with any sharp penetrator having failed to go through armour.

Whether or not the armour is penetrated depends very much on the type of projectile, and what damage would be done if the armour is penetrated (or there is no armour) depends very much on the type of projectile). If armour stops the projectile, then the key things are the projectile energy and mass (or equivalently, energy and momentum, or mass and momentum).

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
View user's profile Send private message Visit poster's website
Marcos Cantu





Joined: 28 May 2004
Likes: 1 page

Posts: 116

PostPosted: Tue 17 May, 2016 4:34 pm    Post subject:         Reply with quote

These discussions always make my head hurt when they get bogged down in the minutia of mass, KE, joules, momentum.

Two things need to happen for blunt force trauma to be a factor in a hit to armor (and this applies to historic or modern ballistics):

1. The struck portion of the armor needs to be making contact with the body
2. The force of the impact (either from a missile or melee weapon) to the armor needs to be enough to cause it to flex inward into the body.

A non-penetrating arrow hit on plate is not going to show any significant BFT. A hammer/mace hit to plate that causes it to dent and push into the body will have some BFT. Whether that is enough to injure will depend on the strength of the blow, how much of the energy of blow was redirected by the armor, and if there are bones or other organs directly under the point of impact. Also, in many of the curiasses I have seen, they are thicker at the center and taper to the sides. An off center hammer blow would hit thinner armor and likely make a deeper dent.

In modern armor ballistics, modeling clay is placed behind armor (hard plates for rifles or soft panels for pistols) to measure the back face signature. The max allowable BFS in the clay is 44mm (more than this and there would likely be fatal internal injuries). Using a modeling clay backing makes it very easy to see the protection a piece of armor provides

I've spent the better part of the last 20 years studying body armor and ballistics and I strongly disagree with those that are saying the principles of historic arms vs armor cannot be compared with modern firearms vs armor. The materials and energy levels may be different but the basic principles are the same. Chainmail and textile armors use the same principles as modern soft armor; plate armor uses the same principles as modern rifle plates. It's all about how to redirect the energy of an impact so that the squishy human under the armor isn't injured
View user's profile Send private message
Mario M.




Location: Croatia
Joined: 31 Mar 2016

Posts: 107

PostPosted: Mon 23 May, 2016 12:04 pm    Post subject: Re: Blunt Force Trauma - Medieval Arrows         Reply with quote

Alec Cawdor wrote:
Just read this interesting blog post about medieval arrows and blunt trauma: http://markstretton.blogspot.com/2016/05/does...rmour.html


His tests are biased as hell, not surprising considering who he is.

He did not even put quilted armor beneath the mail he tested.

As much as I love the guy, everything he does is basically "hur dur archers pwn dur".


To answer your question, perhaps a few primary sources;

"Blaise de Monluc found that his pikemen came to no harm when they closed on a body of English archers at Boulogne in October 1544, writing that 'their arrows did no harm at all' " - The Military Revolution in Sixteenth-Century Europe, David Eltis, page 12


"...among these was a fiery young fighter named Benkin, expert and swift in shooting arrows. He kept going around the walls in the fighting, running here and there, and though he was only one he seemed like more because from inside the walls he inflicted so many wounds and never stopped. And when he was aiming at the besiegers, his drawing on the bow was identified by everyone because he would either cause grave injury to the unarmed or put to flight those who were armed, whom his shots stupefied and stunned, even if they did not wound." - Galbert of Bruges

This, along with the others constantly posted(Joinville, Bahā'al-Dīn and others) all paint a clear picture that those arrows that do not penetrate, do not cause harm.


I personally do not know of a single mention of blunt trauma as a cause of wounds from arrows that hit armored men.

“The stream of Time, irresistible, ever moving, carries off and bears away all things that come to birth and plunges them into utter darkness...Nevertheless, the science of History is a great bulwark against this stream of Time; in a way it checks this irresistible flood, it holds in a tight grasp whatever it can seize floating on the surface and will not allow it to slip away into the depths of Oblivion." - Anna Comnena
View user's profile Send private message Send e-mail
Karl G




Location: Australia
Joined: 25 Apr 2016

Posts: 66

PostPosted: Fri 27 May, 2016 6:16 am    Post subject:         Reply with quote

Philip Dyer wrote:
So, would a sabot (basically minuture dart designed to be able to fire out of a gun) have physics more in common with arrows or bullets? Also, I've noticed that there have been alot of dicussions of 15th and 16th century breastplates and there ability to withstand musket and pistol shoot but no studies of 14th culverins, pipe guns, akes in comparision to earlier breastplates.


Sabots are more like bullets I would say.

The two types of sabots are those used in hunting generally for providing slow calibres such as shotguns, muzzleloaders and pistols to a faster more streamlined bullet for deer hunting. And the second being those used for penetrating hard armour in specialised applications.

To the rest of the thread, physics for penetration and ballistics gets quite terrible and is beyond simple discussions of momentum etc once you get into bullets and pushing envelopes. Post about penetration on a gun forum and you will get a 20 page debate.

Best bet for arrows and normal armour is to keep them out of it.

For example, you could say-

Bullets will penetrate linearly for momentum on wood and semi hard non metallic non shattering substances, may not penetrate linearly on other harder substances but will pass/fail, aka hard metal( for example bullets may not penetrarte partially through hard armour, they either get all the way through or they rebound and get the soldier who fired them ducking!) may also suffer this pass/fail rebound effect if they are for example soft lead and the target is hard wood, they may oscillate their penetrate performance in fluid ( for example more at 2200fps, less if you increase the velocity to 2300fps, then more if you increase it again to 2400fps and so on), they may deform on metal if its harder than them, may shatter it if its hard enough and they are fast enough, may still defeat it whilst deforming if they are big enough and the metal is thin enough. Angles of impact will throw another major spanner in the works varying for nose shape, bullet hardness, target composition and velocities. You may get complete deflection at one angle with one bullet, yet another type will 'dig in' and almost change to a right angled penetration on contact. Also bullets with pointed noses may penetrate well in semi-hard non metallic substances like soft brickwork and wood but won't penetrate straight in fluid media aka animal bodies, (since water is 1000 times more viscous than air where gyroscopic stabilisation by rotation caused by rifling occurs) .Penetration in fluids is best achieved with a type of flat point bullet, also why elephant guns shooting through the largest bodies possible never use pointed bullets. And they believe, but aren't entirely sure this effect is caused by 'super cavitation' or the effect of setting up a bubble in front of their path like a torpedo does, bla bla bla.

Anyone want to relate the physics above to why an arrow will cause blunt trauma on a gambeson is complicating his life Happy

Its best to do what the ballistics experts do. Test 'your object' on 'its target', and record your results. Choose your math after Happy
View user's profile Send private message Send e-mail
Cs. Norbert




Location: Romania
Joined: 21 Aug 2015

Posts: 27

PostPosted: Sun 26 Jun, 2016 5:40 am    Post subject:         Reply with quote

I had a similar discussion on this topic here http://myArmoury.com/talk/viewtopic.php?t=324...highlight= and I think it's possible to inflict serious injuries with arrows (without penetration) but only under special circumstances and only against flexible armor.
View user's profile Send private message


Display posts from previous:   
Forum Index > Historical Arms Talk > Blunt Force Trauma - Medieval Arrows
Page 4 of 4 Reply to topic
Go to page Previous  1, 2, 3, 4 All times are GMT - 8 Hours

View previous topic :: View next topic
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum






All contents © Copyright 2003-2024 myArmoury.com — All rights reserved
Discussion forums powered by phpBB © The phpBB Group
Switch to the Basic Low-bandwidth Version of the forum